And although only 6% of survey respondents identified as upper class, Pew's data shows that 20% of American adults are in the "upper income" bracket.

Pew Research Center

The reason why so many Americans identify as middle class when almost half o them are actually in a higher income bracket is because "in a self-defined classless society, people will naturally not want to separate themselves from their fellow citizens," according to The Brookings Institution.

Economic inequality continues to grow in America. Pew notes that only families in the upper-income bracket have seen a significant increase in wealth since the early 1990s, while the share of adults living in middle-income households is falling.